The principal objective is to detepmine whether significant biological differences may be found in the cellular membranes (erythrocytes and muscle) of patients with Duchenne muscular dystrophy compared to normal individuals, which will provide a clearer understanding of the genetics of the disorder and which will facilitate the identification of female carriers of this disorder. Specific aims include a five-fold study to examine the validity of several methods which may act as proposed markers for Duchenne muscular dystrophy: (1) Studies on red blood cell permeability under conditions of various means of applied stress; (2) development of accurate methods for serum creatine phosphokinase isoenzyme distribution analysis and erythrocyte adenylate kinase isoenzyme analysis; (3) application of a newly devised procedure for erythrocyte membrane "total" ATPase to Duchenne dystrophics; (4) studies on ouabain binding to erythrocyte membrane preparations; (5) electron spin resonance studies on the abnormal cell membrane of the dystrophic and female carrier and also on the diseased sarcolemma during the early phases of the pathogenesis. Final studies will then center on female carrier detection and genetic studies to test the mutation mechanism for the occurrence of sporadic cases and to compare it with alternative proposed mechanisms.